Question 179
Let $M$ be a set consisting of $n$ points in the plane, and satisfying:
(1) there exist 7 points in $M$ which constitute the vertices of a convex heptagon;
(2) if for any 5 points in $M$ which constitute the vertices of a convex pentagon, then there is a point in $M$ which lies in the interior of the pentagon.
Find the minimum value of $n$.
(1) there exist 7 points in $M$ which constitute the vertices of a convex heptagon;
(2) if for any 5 points in $M$ which constitute the vertices of a convex pentagon, then there is a point in $M$ which lies in the interior of the pentagon.
Find the minimum value of $n$.